The existence of important infection-causing ExPEC lineages (i.e., genetically closely related E. coli clones or clonal groups) has been recognized for the past 40 years. However, identification and detailed characterization of specific lineages has only recently been advanced, owing to the development of new methods for bacterial genotyping. Since ExPEC can colonize and persist in the human intestinal tract without detriment to the host, the operational definition of ExPEC is critical for defining the chain of ExPEC transmission from non-human reservoir to human intestinal colonization to active infection.

The tree, which is drawn to scale, was inferred using the Neighbor-Joining method, based on concatenated DNA sequences from the seven MLST loci. E. fergusonii was used to root the tree, but for simplicity has been excluded. All positions containing gaps and missing data were eliminated. There were a total of 3423 positions in the final dataset.

10.1128/9781555817404/fig9-1_thmb.gif

10.1128/9781555817404/fig9-1.gif

Figure 1

The tree, which is drawn to scale, was inferred using the Neighbor-Joining method, based on concatenated DNA sequences from the seven MLST loci. E. fergusonii was used to root the tree, but for simplicity has been excluded. All positions containing gaps and missing data were eliminated. There were a total of 3423 positions in the final dataset.

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110.CoffmanJR,, BeranGW.1999. Issues specific to antibiotics, p 142–178. InNational Research Council: Committee on Drug Use in Food APoAH, Food Safety and Public Health. The use of drugs in food animals: Benefits and risks. The National Academy Press, Washington, DC

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